feat: Support label filtering in vle match search

Author: JoshInnis

postgraph--0.1.0.sql

@@ -6892,7 +6892,7 @@ CREATE OPERATOR @> (
     --JOIN = neqjoinsel
 );
 
-CREATE FUNCTION variable_edge_search(graph_oid gtype, id graphid, min gtype, max gtype, label_filter text[] DEFAULT NULL)
+CREATE FUNCTION variable_edge_search(graph_oid gtype, id graphid, min gtype, max gtype, label gtype)
 RETURNS TABLE  (edges variable_edge, endid graphid, hset hashset)
 CALLED ON NULL INPUT
 STABLE

regress/sql/cypher_create.sql

@@ -171,6 +171,16 @@ MATCH ()-[*1..]->() RETURN 1;
 
 MATCH ()-[:elabel]->() RETURN 1;
 
+MATCH ()-[:elabel*1]->() RETURN 1;
+
+MATCH ()-[:elabel*1..]->() RETURN 1;
+
+MATCH ()-[:elabel*1..2]->() RETURN 1;
+
+MATCH ()-[:elabel*2]->() RETURN 1;
+
+MATCH ()-[:elabel*..2]->() RETURN 1;
+
 --
 -- Clean up
 --

src/backend/parser/cypher_clause.c

@@ -1288,24 +1288,33 @@ add_variable_edge_to_query(cypher_parsestate *cpstate, Query *query, cypher_rela
         edge->name = get_next_default_alias(cpstate);
 
     bool is_default_label = true;
-    if (edge->label)
-        ereport(ERROR,
-                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-                 errmsg("MATCH labels are not supported")));
-    else
+    Node *label_filter = NULL;
+    if (edge->label) {
+        is_default_label = false;
+        label_cache_data *lcd = search_label_name_graph_cache(edge->label, cpstate->graph_oid);
+        if (!lcd)
+            ereport(ERROR,
+                    (errcode(ERRCODE_UNDEFINED_OBJECT),
+                    errmsg("Edge label \"%s\" does not exist", edge->label)));
+
+            label_filter = make_int_const(lcd->id, -1);
+    }else {
         edge->label = AG_DEFAULT_LABEL_EDGE;
+    }
 
     A_Indices *varlen = (A_Indices *)edge->varlen;
 
     return add_srf_to_query(
         cpstate, 
         makeFuncCall(
             list_make2(makeString("postgraph"), makeString("variable_edge_search")),
-            list_make4(
+            list_make5(
                 make_int_const(cpstate->graph_oid, -1), 
                 scanNSItemForColumn(cpstate, vertex_pnsi, 0, AG_VERTEX_COLNAME_ID, -1), 
                 varlen->lidx ? varlen->lidx : make_null_const(-1), 
-                varlen->uidx ? varlen->uidx : make_null_const(-1)),
+                varlen->uidx ? varlen->uidx : make_null_const(-1),
+                !is_default_label ? (Node *)label_filter : make_null_const(-1)
+            ),
             COERCE_EXPLICIT_CALL, -1),
         edge->name,
         list_make3(makeString("edges"), makeString("endid"), makeString("hashset")));

src/backend/utils/edge_searching.c

@@ -227,6 +227,7 @@ typedef struct variable_edge_search_cxt
 	graph_stack_count *current_path;
 	variable_edge_stack *edge_stack;
 	int current_path_length;
+	List *label_filter;
 } variable_edge_search_cxt;
 
 static void
@@ -269,13 +270,32 @@ scan_and_push_neighbors(variable_edge_search_cxt *cxt, graphid id)
     while (table_scan_getnextslot(cxt->scan_desc, ForwardScanDirection, cxt->slot)) {
         cxt->slot->tts_ops->materialize(cxt->slot);
 
+
 		bool isnull;
 		graphid edge_id = DATUM_GET_GRAPHID(
 			heap_getattr(
 				cxt->slot->tts_ops->get_heap_tuple(cxt->slot),
 				1,
 				RelationGetDescr(cxt->scan_desc->rs_rd),
 				&isnull));	
+
+        if (cxt->label_filter != NIL) {
+            bool isnull;
+            Oid edge_label_oid = (edge_id >> ENTRY_ID_BITS);
+
+            bool found = false;
+            ListCell *lc;
+            foreach(lc, cxt->label_filter) {
+                if (edge_label_oid == lfirst_oid(lc)) {
+                    found = true;
+                    break;
+                }
+            }
+            if (!found)
+                continue;
+        }
+
+
 		graphid new_id = DATUM_GET_GRAPHID(
 			heap_getattr(
 				cxt->slot->tts_ops->get_heap_tuple(cxt->slot),
@@ -344,7 +364,17 @@ Datum variable_edge_search(PG_FUNCTION_ARGS)
 		cxt->current_path_length = 0;
 
 		cxt->hashSet = createHashSet(1024);
+		
+
+        cxt->label_filter = NIL;
+        if (!PG_ARGISNULL(4)) {
+			cxt->label_filter = lappend_oid(cxt->label_filter, GT_ARG_TO_INT4_DATUM(4));
+        }
+		
+		
 		scan_and_push_neighbors(cxt, id);
+
+
 		funcctx->user_fctx = cxt;
 
 		MemoryContextSwitchTo(oldcontext);